Painting & drawing blog
CHOOSING PAPER FOR WATERCOLOUR PAINTING
Hot or Not? And other questions…
Although watercolour isn’t necessary the easiest paint to handle, I always think of it as a simpler medium to use than oils, because it doesn’t involve mixing the paint with any spirits or other substances. As far as choosing your watercolour paints go I think this is broadly true: you choose whether you prefer pans or tubes, pick your manufacturer and range, and off you go.
However there is one thing that beginners tend to find very confusing about watercolour painting and that’s the paper you’ll need to work on, because the ways in which different types of paper are defined (especially here in the UK) can often be a baffling lexicon of traditional terms that you may not be familiar with. Here I’m going to try to de-mystify all the different options and help you choose the type of paper that will best suit your level of experience and the type of painting you want to do. This post doesn’t contain any paid links, only my own recommendations.
THE PAPER SURFACE: ‘HOT’ ‘NOT’ OR ROUGH’
This is the first decision you’ll have to make, and these terms all relate to the degree of texture applied to the paper surface during the manufacturing process. All watercolour paper is sold as either ‘Hotpress’, ‘Coldpress’ or ‘Roughpress’ and in the UK these types are usually known just as ‘Hot’, ‘Not’ and ‘Rough’.
‘Hot’ (hot-pressed) paper
Hot-pressed watercolour paper is commonly just labelled as ‘Hot’ in the UK, although a few ranges may describe it as ‘Smooth’ instead. Hot paper is so-called because once the paper pulp has been lifted from its vat of water to form a sheet, it is pressed at high pressure between heated rollers that are covered in a smooth felt. This creates a paper surface with a high density of fibres and with very little ‘tooth’, or texture. Hot is the smoothest watercolour paper you can buy and the least absorbent, because those fibres are so tightly packed together. The density makes is slightly more reflective than the other paper types and due to to this combination of factors your colours may appear slightly more vivid when applied to it.
With Hot paper, because your paint will sit longer on the paper surface before it soaks in it is a little easier to rectify mistakes by immediately lifting off a wash before it dries, using a paper towel or a brush. Your paint colours won’t blend together as easily as they would do with a cold-pressed paper, and layers of washes will be more visible. For some people this is a positive feature – it all depends on your style.
Who would benefit from choosing Hot paper? Because of its fine grain, Hot paper is better for finer details. I use Hot paper because I paint small, detailed portraits in watercolour and with a coarser grained paper it would be much more difficult to control my paint with precision. Hot paper is usually the paper of choice of botanical illustrators who also paint in a detailed and precise way. Many other types of illustrators favour it for the same reason (although equally many prefer the ‘arty’ look of a textured cold-pressed paper) If you wanted to combine watercolour with pen and ink or any other media then Hot paper would be the best option.
‘Not’ (cold-pressed) paper
When I first bought watercolour paints I wondered what on earth ‘Not’ paper could be! In fact the ‘Not’ simply means ‘Not Hot’: in other words, it just means that the paper was cold-pressed rather than hot-pressed. (This strange term in only used the the UK, in the US ‘Not’ paper is simply called ‘Coldpress’) There is an additional difference which is that those cold rollers that the paper pulp is pressed through are covered in a much more textured felt which imprints a coarser surface to the finished paper.
Cold-pressed watercolour paper (medium tooth). Photo credit: jacksonsart.com
‘Not’ paper is what I think of as the classic watercolour paper. It is the most popular and prevalent type due to the artistic effect created as the paint washes sink into the coarse tooth of the paper, encouraging loose and expressive strokes and making it ideal for creating landscapes. Generally speaking the looser your painting style, the rougher the paper texture you’ll likely prefer and if your style is extremely expressive then you may prefer ‘Rough’ paper, as below.
Rough – and ‘Extra Rough’ – paper is like an even grainier version of Not paper. The felt that the pulp is rolled through is highly textured, causing deep pits to be created between the pulp fibres as they are formed into sheets which results in a very granular finish. The textural effects this surface encourages in the paint washes make sit particularly suited to landscape painting or to working in bold expressive strokes. It would be very hard to complete a detailed portrait painting on Rough paper. Sometimes you may also see Rough paper referred to as ‘Torchon’ paper. Torchon is a French word meaning ‘rough textured’ and is also the name given in French to a tea-towel.
Rough-pressed watercolour paper (coarse tooth). Photo credit: jacksonsart.com
As a general note, remember that there isn’t an industry standard for the degree of smoothness of Hot, Not or Rough paper and it will vary very considerably between different manufacturers. It may even vary between paper sold in a loose sheet and that sold in a pad, even when the range is identical. With many paper ranges that produce sheet paper in different weights, the heavier weight tends to be slightly smoother than the lighter weight.
When buying watercolour paper for the first time, it may therefore be helpful to visit an art shop in person rather than buying online so you can compare the surfaces and decide which you prefer. Some online art stores will offer the option to buy cheap samples of their loose sheets of paper. It took me quite a bit of experimentation before I found my favourite type of paper and as we’ll discover, texture isn’t the only factor.
THE WEIGHT OF THE PAPER
This is very important for watercolour paper because of the way that paper will buckle (sometimes called ‘cockling’) when watery paint is applied to it, unless it’s of sufficient thickness and has been correctly prepared.
Where it is sold in large loose sheets, the weights of watercolour paper will vary. Buying loose sheets is therefore something I’d only recommend once you have a little bit of experience with watercolours. If you buy a sheet of paper with a weight of under 300 grams per square metre it will definitely need stretching in order to prevent it from buckling. In the US, 300 gsm is equivalent to 140 lb (most art stores will list both the gsm and the lb weight)
If you do want to start painting on loose, large sheets and you don’t want to worry about stretching it then make sure your paper is at least 300 gsm in weight or preferably higher. Thicker, heavier individual sheets are easily available although you’ll find that at the higher weights they tend to be listed in lbs rather than gsm. You could also go for a ‘watercolour boards’ which consist of sheets of Hot, Not or Rough paper mounted on to a rigid card. These are up to three millimetres thick (1/8 inch) and will definitely not require any stretching.
Watercolour board. Photo credit: jacksonsart.com
Even 300gsm paper may have a tendency to buckle a little depending on the washes you apply to it, and I find it necessary to tape it down to a board to keep it flat – more about this further on. One way to avoid the problem altogether is to buy a ‘block’ of paper where the sheets are glued to each other at the edges to keep them flat whilst you work on them. With this in mind let’s now look at the different formats for buying paper.
FORMATS FOR BUYING WATERCOLOUR PAPER
Watercolour paper is sold as loose sheets or cut from a roll in an art store, or in glued pads, or gummed ‘blocks’. Sometimes you can also buy packets with a number of loose pieces of small size sheets
Loose paper sheets
Loose paper is sold in large sheets (which you can ask an art store to cut down for you for free into halves or quarters) or cut off a roll. Aimed more at professionals or experienced artists, loose paper is usually of high quality and handmade or mould-made rather than machine-made, as we’ll discuss below. Many online art shops will allow you to order small paper samples of their loose sheet paper, like these.
With watercolour paper sizes a lack of industry standards can again make things rather puzzling. Loose leaf paper, gummed pads and blocks may all be sold in either imperial (inches) or metric (centimetre) sizes, depending on the manufacturer. When watercolour paper is sold is sold in loose leaf sheets cut to metric sizes these usually do NOT equate to the European A size system (A4, A3 etc). Instead most ranges manufacture loose paper sheets as either ‘Full Sheets’, ‘Half Sheets’ or ‘Quarter Sheets’. A full sheet is also known as Full Imperial and is 30 × 22 inches, which is a little smaller than the European A1 size. A Half sheet will be 15 x 22 inches, and a Quarter sheet is 15 x 11 inches.
Sometimes loose paper is simply sold by the inch instead, the most commonly offered sizes being either 30 x 22 inches or 16 x 20 inches. Paper sold in metric measurements generally comes in a wider variety of sizes including a common size of 55 x 76 cm, which very roughly equates to a Full Imperial sheet.
Paper in pads
When paper is sold in a pad it will always be gummed together or spiral bound on the ‘short’ end. Pads are typically what beginners will start with and are more economical than buying paper in a block, but usually cost more than buying a large sheet and cutting it down. Pads of paper vary in quality from much cheaper ranges made with wood pulp to the most expensive cotton fibre paper. We’ll discuss these distinctions further down.
Pads are sold in either in imperial or metric sizes, which will sometimes conform to the European A4 and A3 formats. Usually the more expensive the paper, the more likely it will be sold in imperial (inch) measurements rather than ‘A’ sizes, however. For example Daler-Rowney’s professional quality ‘Langton Prestige’ watercolour pads are sold in pads and blocks in a variety of inch sizes, whilst their cheaper ‘Langton’ range is sold as A4 and A3 sized pads. The vast majority of glued pads will be made from 300gsm paper, although some cheaper ranges may weigh less and are therefore to be avoided except for quick sketching practice.
Blocks are usually made with the higher quality cotton fibre paper of at least 300gsm. They are available in Hot or Not finishes, but are not often made with Rough paper because it’s more difficult to bind. The point of buying paper in a block is the way that all the sheets are fixed to each other to keep them entirely flat whilst you work on them. The sides of the paper pad are coated with a black glue that holds them together all the way around, apart from a small area within the top edge of the pad where there is a little break in the binding.
To use a block, you open your pad and make your first painting on the top sheet of paper. It may appear to be buckling a little whilst the paper is wet but once the paint has dried your paper will shrink back and appear completely flat again. When you’re finished you take a palette knife (a kitchen knife with a bit of bend in it would work for this too, or a craft knife if you are very careful) and insert it into the break in the gummed side of the block, gently levering the sheet with your painting off. Then you start your next painting on the sheet below, which becomes the top sheet.
Blocks may be produced in either imperial or metric measurements but rarely conform to A3 or A4 sizes, in the latter case. They are most likely to be used by professionals, who tend to think that the A4 and A3 formats are a little displeasingly ‘letter box’ shaped (however if you actually are seeking a really wide format paper to paint panoramic landscapes on then Arches make a 6×12 inch very rectangular shaped block that you might like.)
This guide is really aimed at beginners who are trying to work out what sort of paper to buy, and as already mentioned if you are new to watercolour painting I would suggest avoiding buying sheets of paper that’s less than 300 gsm in weight because you’ll have to stretch it. This is particularly important with loose leaf paper, because big sheets will buckle the most when washes are applied to them.
Stretching watercolour paper is done by soaking it in water for a few minutes and then using gummed paper to stick it to a flat board such as a sheet of MDF, or a purpose made wooden board from an art shop. If you do want to stretch your paper there are plenty of tutorials online that will describe the process for you. Alternatively there are ‘paper stretchers’ available from art stores which have a frame to clamp your wetted paper down whilst it dries. Stretching is likely to result in the loss of some of the paper’s sizing, and so I’d really recommend avoiding buying lightweight watercolour paper when you’re starting out with watercolours.
Jackson’s smooth panel wooden art board. Photo credit: jacksonsart.com
It’s often said that a paper of 300gsm or above won’t buckle when painted on, but in fact I don’t find this to be entirely true which is why I prefer to buy blocks so that my paper is conveniently held flat. If I am using loose sheets or paper from a gummed pad then even at 300sgm I find that a slight buckling occurs if I apply a few washes. Therefore although I don’t bother to wet my loose paper I do like to tape it down to a board using gummed paper strip or low-tac masking tape (this also creates a neat edge around my painting when I remove it afterwards). If I still find my paper isn’t completely straight when it’s dry then leaving it under a few heavy books for a few days will usually flatten it satisfactorily. Some people like to spritz the back of their painting with a spray or moisten it with a brush a little before flattening it or ironing on the reverse.
PAPER TYPES AND TREATMENTS APPLIED
Proper watercolour paper is made with one of two materials: cotton fibres, or wood pulp. Occasionally they are made from a mixture of the two and may contain 50% of each, or 25% cotton to 75% wood pulp.
Cotton fibre paper
Paper made from cotton fibres (to which linen fibres may sometimes be added for extra durability) is considered to be of professional quality due to its strength and conservational qualities. It has longer, stronger fibres than paper made from wood, is completely acid free and shouldn’t turn yellow and become brittle over the years. Therefore if you want to sell your work commercially then using cotton fibre paper is really a must.
Because cotton fibres are tougher than wood pulp fibres, cotton paper can better withstand any erasing of under drawings, multiple paint washes and scrubbing and lifting off of paint without damage to its surface. With the best quality cotton papers you can even remove dried paint by re-wetting it and gently scrubbing with a brush without the surface becoming fibrous or ‘furry’. It’s also generally acknowledged that cotton fibre paper is easier to blend washes on.
‘Wood-free’ wood pulp
Cheaper watercolour paper is made from wood pulp. In the UK this is sometimes confusingly often described as ‘wood-free’ paper. The name is just a shortening of the term ‘groundwood-free’ which means that the wood pulp was broken down chemically rather than being ground down mechanically. The significance of this method of production is that when wood pulp is broken down and bleached with chemicals it removes the ‘lignins’ in the cellulose. Lignin is the substance within that holds wood fibres together but it is also responsible for the acid damage that will occur to paper over time and cause it to turn yellow. Removing lignin also strengthens and whitens the paper.
It must be said that whilst the treatments applied to wood pulp paper will remove most of the acid, only cotton fibre paper is actually ‘acid-free’ because it contains no lignins to start with. When wood pulp papers state that they are acid free this suggests that they have made from chemically treated paper but is not necessarily always the case. Some cheaper papers will claim to be ‘acid-free’ or ‘acid-neutral’ simply because they have had an alkali solution added to give the paper a neutral pH (more on this below). This very cheap type of paper will yellow as its ingredients change colour over time, and will also be unlikely to contain the anti-fungals that are added to better quality ranges.
If a paper doesn’t proudly state that it is made from cotton fibres, then it is very unlikely to be a cotton paper. In the UK most papers made from treated wood pulp will declare the fact, but this is less true in the US. In both countries treated wood pulp is sometimes described as ‘Archival Cellulose’ or as ‘High Alpha Cellulose’. This is a little confusing because both cotton fibres and wood pulp both contain alpha cellulose, which is the strongest type of cellulose extracted from plants – in fact cotton contains 100% alpha cellulose. Wood pulp paper contains less alpha cellulose and hence is not as strong. However if you see ‘Alpha Cellulose’ paper on a watercolour pad it indicates that it is made from wood pulp paper and not cotton. If it says ‘Archival’ or ‘High Alpha’ as well, this indicates that it has been chemically treated to remove lignins.
What is wood pulp paper like to work on? It definitely isn’t as durable as cotton fibres and it won’t take washes, scrubbing and lifting off of paint so well without damaging the paper surface. Most people find that the paint doesn’t stay manipulable as long or blend as well on it. It’s marketed as a beginner or student grade paper though I would suggest that if you can possibly stretch to it then you will enjoy painting onto cotton fibre paper much more.
‘Buffering’ is another positive description to look out for, and will indicate that a neutralizing chemical has been added to the paper pulp during the manufacturing process to create what is known as an ‘alkali reserve’. This is designed to create a higher and less acidic PH and to counteract any acid-containing pollutants the paper will be subjected to in the atmosphere, from paint, or from framing processes. Measuring the pH of paper isn’t an exact science, but in general a ‘pH alkalinic’ paper (ideally between pH7 & pH8) will be more archival than a ‘pH neutral’ one.
In some ranges of watercolour paper, shades of ‘Extra White’ or ‘High White’ are available. This designation indicates that a little bleach and/or some Titanium Dioxide pigment has been added to the pulp to whiten it. Be aware that contrary to what you might expect even extra or high white watercolour paper still isn’t really bright white – all watercolour paper is at least slightly creamy.
You will often notice that the better quality papers are described as being ‘Free from OBAs’ which stands for ‘Optical Brightening Agents’. These are chemicals added to the paper pulp which can take invisible ultraviolet light and cause it to fluoresce, thus causing the paper to appear whiter. However they are unstable and quickly lose this whitening effect, meaning that your paper will change its shade in a fairly short space of time. Some cheaper watercolour ranges will use OBAs but won’t always state it…however if they don’t include ‘Free from OBAs’ in their description it is fairly likely that these have been added to the paper.
HAND-MADE, MOULD-MADE OR FOURNDRINIER PAPER
There are three methods for manufacturing watercolour paper and here once again we find some slightly confusing terms. Let’s run through the different methods of paper manufacture and the differences between the papers they produce.
‘Hand-made’ paper is the most straight forward and self-explanatory type. When paper is truly hand made, the pulp (usually cotton) is immersed in water and a mesh covered frame and deckle are submerged in the mixture by hand and agitated so that an even layer of the pulp settles on the mesh. This layer is then removed by placing it onto another piece of felt, pressed flat, and dried. Hand-made paper is often thicker than most other types, fairly rough in texture and has four lovely deckled (ragged) edges. However it may not be quite as consistently durable as ‘mould-made’ paper (see below) because it’s a little more irregular.
Mould-made (also known as ‘Cylindrical Mould’ paper)
Most top quality watercolour paper is ‘mould-made’ which sounds as if it is also made by hand but actually involves a mechanised process whereby cotton fibre pulp is lifted from a stainless steel vat by a rotating cylinder, covered in a wire mesh. The wire-covered cylinder is partly suspended above and partly submerged within the water, and is rotated around in it to pick up a layer of fibres onto its mesh covering. The layer of fibres is then deposited onto a rotating roller covered in woollen felt called ‘carrier felt’.
Next the water is pressed out of the pulp and then the sheet is pressed between rollers covered in ‘marking felt’ which gives the paper its texture. For ‘Hot’ paper the rollers will be hot and the felt quite smooth, whereas for ‘Not’ paper the rollers are cold and the felt much rougher. Mould-made paper will have two deckled edges rather than four, and two smooth edges where it is cut from the roll.
This way this type of paper is made accounts for the difference in texture you’ll often find in mould-made paper between one side and the other. The ‘felt’ side’ is the side where the fibres were in contact with the woolen carrier felt as they were lifted out of the water, whereas the ‘wire’ side is the side that was in contact with the wire mesh that covers the cylinder. With mould-made paper you’ll usually notice that one side is slightly more textured than the other and this is because you are seeing the ‘felt’ side. It’s fine to paint onto either, but the felt side is considered to be superior whereas on the ‘wire’ side the imprint of the fine mesh may still be slightly visible. Most sheets of loose watercolour paper will carry a maker’s watermark that is imprinted from a metal seal attached to the cylinder mould, and the side this mark appears on is considered to be the front of the paper.
If paper doesn’t state that it is either hand made or mould made then it is pretty certain to be ‘Fourdrinier’ paper. Fourdrinier paper is entirely machine-made and is named after the Fourdrinier Machine, invented at the turn of the nineteenth century and on whose principles modern paper making machines are still based . This type of machine is the cheapest and most automated method of producing paper and is generally used to produce the lowest quality ‘student’ ranges of watercolour paper.
On a Fourdrinier style machine the fibre pulp is pushed onto a moving mesh roller and as it travels along the roller the water is removed and the fibres are aligned in the same direction (with mould-made paper at least 50% of them face in random directions, making it stronger). The paper is then pressed between felts and dried. Because the fibres all end up facing the same way, machine made paper lacks the lovely texture and strength of mould paper and is prone to distortion when wet.
GELATIN AND STARCH SIZING
Nearly all watercolour paper will come already sized with gelatin (there are also a number of papers sized with starch or acrylic sizes which you can search out if you’re vegetarian or vegan and would rather avoid animal-based products. This post has a list) Watercolour paper requires sizing to give it some resistance against the watery washes applied to it and without it would soak them up like blotting paper in an uncontrollable way. As well as the choice of grain of your paper (hot, not, or rough) sizing is a really critical factor in how your paper takes watercolour and whether the edges of the paint ‘bleed’ and appear fuzzy – a characteristic that some artists may like and others may not. It’s very subjective.
Sizing also has a number of other purposes. It helps prevent the paint from cockling the paper, allowing the fibres to sink back into place as they dry and keeping it flat. It helps the paper absorb moisture more evenly creating a more consistent colour within a wash. Because sizing allows more of the paint to dry whilst sitting on top of the paper surface it’s addition also results in your colours being more vivid.
The main benefit of sized paper though is that it aids your ability to correct mistakes because when you want to lift off or scrub away an area of paint some of the size scrubs off with it, leaving the paper beneath intact. Size may be applied in either a thin or a heavy layer (known as ‘hard sized’), and the more size is added the less absorbent the paper will be, allowing you to remove some of the paint before it has fully soaked into the paper and without destroying its surface. It’s instructive to think of paper as really just a lot of tiny fibres stuck together: the more those fibres are agitated by washes, scrubbing, or the blotting of paint, the looser they will become until the paper’s surface becomes compromised and your paint starts blotching in ways you don’t want it to. Size helps to prevent this from happening too quickly.
Sizing can be both ‘Internal’ or ‘External’. ‘External’ means it has been applied to the paper after it’s been made into sheets by soaking these in a size (sometimes it will be described as ‘gelatine tub sized’). ‘Internal’ sizing means that a size was added to the pulp and water mixture before the pulp was turned into paper. The top quality papers have both internal and external sizing. Internal sizing gives strength and durability and keeps colours from soaking in right to the core and losing their vividness, whilst the external tub sizing gives the paper its initial resistance to the wash. Ideally both are helpful. Confusingly although most cheaper papers are externally sized only, a few (Bockingford for example) are just internally sized.
Since different types of watercolour paper have different amounts of size applied both internally and externally, they will perform differently. Although as we have noted a ‘Not’ paper is more absorbent than ‘Hot’ paper, if you do want a textured paper that’s less absorbent there are papers available that are roughly textured BUT have a hard tub size, making the paint absorb more slowly. Really the only way to find one that suits your working method is to experiment with several until you discover which you like best. Some manufacturers add excessive sizing in part to compensate for the size that is lost if people stretch their paper, and with these papers you may find that your paint just sits on the top of the paper in an unsatisfactory way.
Which make of paper should you buy?
Let’s see if we can now summarize a bit. If you are aiming to paint professionally then there’s no question that you need to go for the best archival quality, which means cotton fibre and not wood pulp paper. If you are painting just for pleasure then wood-pulp paper is ok, but you may want to experiment with different papers until you find one with the right amount of sizing for your painting style. Stick to 300gsm paper to make sure your paper won’t buckle if you don’t want to go to the trouble of stretching it yourself. If buying wood pulp paper, go for something mould made and avoid machine made brands, because you’re likely to get better results and the paper is more likely to have been both more thoroughly treated to remove the lignin content and also buffered with an alkali reserve. Try as many as you can until you find one that works best for you. People tend to have strong favourites in terms of absorption, colour and so on.
For example the most famous and exalted range of watercolour paper is the ‘Aquarelle’ range made by French paper mill Arches (pronounced ‘Arsh’) which is one of the oldest in the world. On paper it ticks every box, being a cotton fibre paper, mould made, and gelatin sized to the core. It’s made only during certain times of the year because the water from the river used to wash the paper becomes too muddy during the winter! It’s undoubtedly a top quality paper and is very durable and strong, but some people find it too absorbent and prefer something with a slightly harder size like my favourite ‘Fabriano Artistico’ which allows them to lift paint off more easily. The point is that everyone is different and different papers will suit different artists.
Many companies will make both a cheaper range and a more expensive one, so it is really a question of choosing a paper range, rather than a manufacturer. For instance both of Daler-Rowney’s standard ‘Langton’ and more expensive ‘Langton Prestige’ papers are mould-made, but the former is a wood pulp paper and the latter is made from cotton fibre. Winsor & Newton also make two mould-made ranges: their ‘Classic’ range which is a wood pulp paper and their ‘Professional’ cotton fibre paper. Canson’s ‘Moulin de Roy’ is a cotton cylinder mould paper which is internally and externally sized whereas their ‘Heritage L’Aquarelle’ whilst also made from cotton and a very good paper too, is externally sized only and slightly cheaper. A very good manufacturer is the long established St Cuthbert’s Mill who make very famous papers called ‘Saunders Waterford’ and ‘Bockingford’, both of which are mould-made. The Saunders is a cotton paper and both internally and externally sized, whilst the Bockingford is made from wood pulp and is internally sized only.
I’ve put together a handy list of the watercolour papers from well known manufacturers here, which compares their methods of manufacture, availability in different formats and the type of sizing used.